In‐plane anisotropic permeability characterization of deformed woven fabrics by unidirectional injection. Part II: Prediction model and numerical simulations

Abstract

The production of polymer composites by resin injection has strongly increased in the recent years for a wide variety of industrial applications. Manufacturing techniques are continuously optimized for higher and faster production cycles and high performance composites are needed to meet industrial requirements. Actually, the reduction of cost and cycle time is the main motivation for liquid composite molding (LCM) process simulation. In this context, the characterization of preform permeability is a key issue in numerical flow analysis. This investigation concerns the experimental study and development of a predictive model for deformed fabric permeability. Such deformations occur when a fabric is draped on a complex surface. A local shear appears. In Part I, an experimental procedure has been described to measure the permeability of deformed fabrics, and a new methodology presented to characterize the in-plane permeability tensor. In order to implement experimental results in numerical simulation, a permeability model for deformed fabrics is required. Part II develops a predictive model of the principal permeabilities of deformed fabrics and of the orientation of the permeability tensor. Based on unsheared fabric measurements, the model takes into account the unit cell deformation during shear and the initial elliptic flow pattern orientation and anisotropy ratio of undeformed fabrics. Model predictions are corroborated with sheared fabric measurements. Finally, numerical simulations for an automotive body part are carried out to illustrate the effects of fabric shearing on the filling of the composite part. POLYM. COMPOS., 28: 812-827, 2007.

Boundary element approaches for filling simulations of anisotropic reinforced preforms used in the resin transfer molding process

“…Invoking the research of DeMarı´a et al 39,40 the Kozeny term, r 2 f =4k, depends on the fiber volume fraction, V f , and on the orientation of the preform, .…”

Guiding selection for reduced process development time in RTM

“…It begins by placing a dry reinforcement (fibres) inside a rigid mold, closing the mold, injecting a liquid resin, curing the resin and finally demolding the part. Many numerical models have been developed to predict each steps of the RTM process leading to commercial software, such as QUIK-FORM and PAM-RTM [4]. Nowadays, such simulation software are widely used by large RTM manufacturers to predict and improve molding conditions.…”

A Prediction Method for In-Plane Permeability and Manufacturing Applications in the VARTM Process

“…Sun [7] and Ni [8] set up a device to visualize the experimental results and measurements of permeability. Wang and Demaria [11][12][13] characterized the in-plane permeability of woven fabrics and proposed a predictive model. Wu [14] and Nedanov [15] researched the trans-plane permeability by theory and experiments to describe 3D permeability of fiber laminates.…”

“…The VARTM simulation involves with parameters, such as the viscosity of resin, the porosity and permeability of fiber laminates. The permeability of FRP laminates is critical in the manufacturing process and numerous researchers have investigated the measurements and analytical models of permeability [7,8] [ [11][12][13][14][15]. Sun [7] and Ni [8] set up a device to visualize the experimental results and measurements of permeability.…”